Roasted Asparagus Lasagna
serves eight to ten
This rich lasagna is so wonderful all your friends will rave. It’s great to serve in the spring when the asparagus is fresh. It makes an elegant pasta course but also works well as an entreé.
For the béchamel:
5 tablespoons unsalted butter
3 tablespoons unbleached flour
1 1/2 cups hot milk
1/2 teaspoons coarse (kosher) salt
For the filling:
2 tablespoons plus 1 teaspoon pure olive oil
2 large onions (1 pound), halved vertically and thinly sliced
2 pounds fresh asparagus, trimmed
1/2 cup plus 1 tablespoon heavy cream
1 1/4 cups freshly grated Parmigiano-Reggiano cheese (about 3 1/2 ounces)
Twelve 1/8 inch thick slices fresh mozzarella cheese (about 4 ounces)
1/2 teaspoon salt
For the pasta:
4 wide fresh lasagna noodles
1/2 teaspoon salt
1. In a heavy medium saucepan, melt 3 tablespoons of the butter over low heat. Add the flour and stir with a wooden spoon until thoroughly incorporated. Cook, stirring, until the mixture has bubbled for 1 minute; do not allow the flour to brown.
2. Remove from the heat and very slowly whisk in the hot milk. Return the saucepan to low heat and cook, whisking until the sauce thickens and loses its flour taste, about 10 minutes. Stir in 1/2 teaspoon of the salt and transfer to a bowl. Press a piece of plastic wrap or wax paper directly on the surface of the sauce and set aside. (The béchamel can be made several hours ahead; let cool to room temperature and refrigerate. It will thicken as it cools; rewarm it very slowly until it reaches spreading consistency before using.)
3. Preheat the oven to 500°. In a large skillet, melt the remaining 2 tablespoons butter in 1 tablespoon olive oil. Add the onions and sprinkle with 1/2 teaspoon of the salt. Cook over low heat, stirring occasionally, until very soft and lightly colored, 15 to 20 minutes.
4. On a baking sheet, toss the asparagus with the remaining 1 tablespoon olive oil until evenly coated. Spread them in a single layer and bake until tender, about 10 minutes. Remove from the oven and let cool slightly. Thinly slice the asparagus on the diagonal and add to the onions. Reduce the oven temperature to 375°.
5. In a large saucepan, bring 5 quarts of water to boil and add the remaining 1/2 teaspoon salt. Drop the lasagna noodles into the boiling water and cook until soft and pliable, about 3 minutes for fresh. Drain and lay the lasagna noodles on a damp tea towel. (If using fresh pasta, refresh the noodles under cold running water to stop the cooking process and to prevent the noodles from sticking together.)
6. Set aside 2 tablespoons of the béchamel sauce, 1 tablespoon of the heavy cream and 1/2 cup of the Parmigiano. To assemble, spread 2 tablespoons of the béchamel on the bottom of an 8-inch square baking pan and drizzle 2 tablespoons of the heavy cream on top. Cover with one lasagna noodle and 2 more tablespoons of béchamel. Spread 1 cup of the asparagus and onions on the sauce, cover with 4 slices of the mozzarella and sprinkle 1/4 cup of the Parmigiano on top. Drizzle with 2 tablespoons of the heavy cream. Top with another noodle and repeat the layering twice, using 2 tablespoons of béchamel, 1 cup of the asparagus and onions, 4 slices of mozzarella, 1/4 cup of the Parmigiano and 2 tablespoons cream each time. Cover with the last noodle and spread the reserved béchamel, cream and Parmigiano on top.
7. Cover the lasagna loosely with foil and bake for 10 minutes. Uncover and bake for an additional 20-30 minutes, or until golden and bubbling. Let cool for 10 minutes before cutting.